Moreover, prognostic analysis of both PDCD4 and miR-21 expression showed that neither of PDCD4 nor miR-21 can be used as independent prognostic factor in our study, which is inconsistent with Ren et al.'s conclusion that miR-21 expression was an independent prognostic factor indicating poor survival and which is consistent with Cao et al.'s [18] results that PDCD4 was not an independent prognostic factor in gastric cancer with 187 cases of patients; the possible reason contributing to the discrepancy may be that samples enrolled to be insufficient to arrive at statistical significance. This evidence concerns the gene PDCD4 and gastric cancer.